The present invention relates to a vehicle control apparatus for informing a driver of an emerging risk when a safety function does not work due to a quantity of residual electrical energy of a battery being insufficient.
In addition, the invention relates a vehicle control apparatus and more particularly to a vehicle control apparatus which includes an economical running (or idling stop) function in which a vehicle is driven while repeatedly driving and stopping an engine.
Furthermore, the invention relates to a vehicle control apparatus for restricting feeding to a load such as on-board electric equipment or the like which is connected to the battery, a vehicle control method and a vehicle slip suppressing unit.
Several electronic control units are mounted on a vehicle which include, for example, an engine ECU for controlling the amounts of fuel to be injected and air to be let in, a charge control ECU for controlling the charging of a power supply, a body ECU for controlling the locking of doors and the like, an automatic transmission (AT) control ECU, an airbag ECU, a security ECU for producing an alarm when theft has happened or an event has been detected which indicates the occurrence of theft, and the like.
With development of electronic control in conjunction with propagation of automobiles and propagation of on-board components which are required in pursuit of convenience, comfortableness and safety, the fitment of on-board electric equipment such as those described above has drastically been increased, and a feeding system, that is, a battery has been forced to bear an increasing load. In these circumstances, since when the quantity of residual electrical energy in the battery is decreased or becomes insufficient, there will be caused a problem in operation of the vehicle, it is a conventional practice to inform in advance the driver of the reduced or insufficient residual electrical energy in the battery as it actually occurs.
On the other hand, in guiding a vehicle by a car navigation system, points where the vehicle has to be driven with care or care requiring points such as risky points on road surfaces where joints and pits are situated, entering points to road surfaces such as rough road surface covered with pebbles which give shocks to the vehicle and make the driver uncomfortable while he or she is driving the vehicle and other risky points are recorded on an electronic map, so that when the vehicle is approaching or passing through the recorded points, the driver is informed that the vehicle is approaching or will soon be passing through the relevant points by way of a warning displayed on a screen of the navigation system or in voice generated thereby.
However, since it is difficult for the user to input these points, there has been proposed a technique in which vibrations from a road surface or shocks from the road surface are detected, and positions where the vibrations are detected are then located, so that information on the vibrations so detected and information on the positions so located are recorded in map information in such a manner as to be associated with each other, whereby vibration generating point information which is associated with the respective points on the map is automatically recorded without depending on the input of the relevant points by the user (for example, refer to Japanese Patent Publication No. 2001-4382A).
As has been described above, it is the conventional practice to inform in advance the driver of the reduction in electrical energy of the battery as it actually occurs. However, giving the driver the information in the stage where the electrical energy of the battery is so reduced may be too late, since, when the driver continues to drive the vehicle after he or she has been informed of the reduction in electrical energy of the battery, there is a possibility that various safety-related functions mounted on the vehicle may not be able to work properly, which results in a risky driving.
In addition, as is proposed in the Japanese Patent Publication No. 2001-4382A, there exists the technique in which when the vehicle is approaching or will soon be passing through the care requiring point such as the entering point to the road surface where shocks are given to the vehicle while it is being driven and the risky point, the driver is informed in advance by the indication on the screen or in voice of a risk which waits ahead of his or her vehicle. However, this technique is not such as to inform the driver whether or not the safety functions can operate properly.
In recent years, for the purposes of improving fuel economy and reducing exhaust emissions, an automatic engine stop and restart control (a so-called economical running control) is adopted in which an automatic engine stop instruction is issued when predetermined engine stopping conditions (a driving history exists, the vehicle is at halt, the engine is idling, and the like) are established, and thereafter, when predetermined engine starting conditions (the brake is released, a gearshift occurs, the accelerator pedal is depressed, and the like) are established, an automatic engine restart instruction is issued so as to drive an engine starter motor.
Namely, in stopping at traffic lights or the like, there has been caused a problem that when the engine is left idling while the vehicle is not actually driven or is at halt, exhaust gases continue to be produced and fuel consumption is increased. Because of this, the engine is temporarily stopped while the vehicle is being stopped at traffic lights or the like, or the accelerator pedal is left released for a certain period of time as the vehicle is coasting, and with the engine stopped temporarily like this, when the accelerator pedal is depressed again, the engine is restarted to start the vehicle.
According to this economical running control system, the engine is made to be driven only when it is needed for driving the vehicle, whereas the engine is stopped on other opportunities, whereby the feel economy can be increased, and the engine driving time can be reduced so as to reduce the amount of exhaust gases.
In vehicles equipped with the economical running function like this, in order to improve driving comfortableness, accessories such as audio equipment and the like are configured to be usable while the economical running (or the automatic engine stop) is in operation. In the event that the battery voltage is decreased by the usage of the accessory while the engine is stopped, however, a sufficient driving current cannot be supplied to the starter motor, and the engine restarting capability is deteriorated. Therefore, to cope with this, there has been proposed a technique in which the economical running is prohibited when the battery voltage is decreased (for example, refer to Japanese Patent Publication No. 2002-115578A).
In addition, when the battery voltage is decreased, the usage of electric equipment is increased to apply high load to the battery, or the quantity of current to be generated by the alternator is small, there is produced a possibility that a shortage of power supply to safety systems designed to prevent accidents may occur, and, therefore, to cope with this, there has been proposed a technique in which feeding to the air conditioner and other entertaining electric equipment is stopped (for example, refer to Japanese Patent Publication No. 2002-199505A).
As has been described above, conventionally, there have been proposed the techniques in which when the battery voltage is decreased, the economical running is prohibited and the feeding to the unnecessary electric equipment for safety driving is stopped so as to prevent the shortage of power supply to the safety-related systems.
However, in the event that the economical running is permitted in such a state that the vehicle is approaching a risky area such as a place where the safety systems are activated to operate, whereby a shortage of feeding is likely to be caused, when the vehicle is actually driven in the risky area, a shortage of feeding is called for, leading to a possibility that feeding to the safety-related systems may become insufficient.
An electronic control unit (hereinafter, referred to as an ECU) of a vehicle is such as to exchange signals with control mechanisms of the vehicle so as to electronically control the vehicle. For example, pieces of information on vehicle speed, engine speed, intake air amount and the like which are detected by a group of sensors mounted on the vehicle are inputted into an engine ECU, and the engine ECU executes a predetermined arithmetic processing based on the pieces of information and sends out the results of the arithmetic (or example, signals to control the quantities of fuel to be injected, by-pass air and the like) to control mechanisms mounted on the vehicle such as an electric throttle, a starter injection valve and the like so as to control the quantities of fuel to be injected and air to be let in.
Several electronic control units like this are mounted on a vehicle which include, for example, an engine ECU for controlling the amounts of fuel to be injected and air to be let in, a charge control ECU for controlling the charging of a power supply, a body ECU for controlling the locking of doors and the like, an automatic transmission (AT) control ECU, an airbag ECU, a security ECU for producing an alarm when theft has happened or an event has been detected which indicates the occurrence of theft, and the like.
In this way, with development of electronic control in conjunction with propagation of automobiles and propagation of on-board components which are required in pursuit of convenience, comfortableness and safety, the fitment of on-board electric equipment such as those described above has drastically been increased, and a feeding system, that is, a battery has been forced to bear an increasing load. Therefore, the load applied to the battery has been tried to be decreased by controlling the quantity of electric current that is generated by a generator according to the using conditions of the electric equipment, battery conditions and vehicle running conditions (for example, refer to Japanese Patent Publication No. 7-298694).
On the other hand, various safety-related equipment such as AFS, EBD, ABS, VSC, TCS, PCS are mounted on vehicles. Namely, the AFS (a movable lighting system or Adaptive Front-lighting System) is such that projector units of headlights are linked with the operation of a steering wheel in such a manner that directions thereof are changed to a direction in which the vehicle is steered when running on a curve or turning right or left at an intersection so as to illuminate a traveling direction of the vehicle. The EBD (electronically controlled brake force distribution system or Electronic Brake force Distribution) is a system in which a distribution of brake force (brake distribution) to front and rear wheels at the time of application of the brakes is controlled by a computer so as maximize the braking potential.
In addition, the ABS (Anti-lock Brake System) is such as to prevent wheel lockup when a panic brake is applied in slippery road conditions, and the VSC (a skid preventing function or Vehicle Stability Control) is a system for asking in application of a steering torque in a direction in which the behaviors of the vehicle are stabilized according to a steering angle of the steering wheel. Furthermore, the TCS (Traction Control System) is a system for preventing wheel spins at the time of acceleration of the vehicle by controlling the vehicle torque when such wheel spins are detected, and the PCS (Pre-Crash Safety System) is such as to increase the occupant restraining performance by retracting the seat belts of the driver's seat and front passenger's seat when a brake applied is judged as art emergency brake from a speed at which the brake pedal is depressed.
As has been described above, conventionally, in order to reduce a load that is applied to the battery, the quantity of current that is generated by the generator is controlled according to the usage of the electric equipment and the battery conditions and vehicle driving conditions. However, even in the event that the quantity of current generated by the generator is so controlled, when the aforesaid various safety systems are activated in fear of the occurrence of an accident, a required quantity of electrical energy exceeds the capacity of the generator, causing a possibility that a shortage of feeding may happen, resulting in a possibility that the safety equipment may not be activated for operation.
Additionally, in a conventional vehicle slip suppressing unit for preventing an accident by the use of information from a navigation system, a driving control is performed by calculating a permissible speed and a permissible G in consideration of information from the navigation system, the state of the vehicle and the road conditions. However, only the conditions of the subject vehicle is taken into consideration, and weather and temperature or a driving environment such as the condition of the driver is not taken into consideration, whereby a permissible G cannot be calculated accurately, resulting in a risk that a slip avoidance control fails to be performed.